Electrical contacting of thin enameled wires of secondary windings of ignition coils

ABSTRACT

An electrical connection set-up for manufacturing an ignition coil is provided, e.g., for connecting thin enameled wires in ignition coils. In this regard, on the side of the high-voltage outlet, a contacting sleeve is provided which is installed by being lifted over a corresponding secondary winding without making contact and which then snaps into place due to the spring-like form or mounting, while elements provided on the contacting sleeve break through an insulating layer surrounding the secondary winding, thus establishing the electrical connection without the use of thermal methods.

FIELD OF THE INVENTION

The present invention relates to an electrical connection set-up formanufacturing an ignition coil, particularly a rod-type ignition coilhaving an ignition coil rod with a high-voltage outlet.

BACKGROUND INFORMATION

Ignition coils may produce a high-voltage spark, which jump between theelectrodes of the spark plug set up at the ignition coil, thus ignitingthe air-gasoline mixture of an internal combustion engine, for example.This spark plug may be supplied with high voltage from an ignition coil.A primary winding and a corresponding secondary winding may be providedwithin the ignition coil. At one end, the primary winding may beconnected to an ignition switch, while its other end may be connected toa so-called contact breaker.

The secondary winding, that is, the winding responsible for generatingthe ignition spark, may be connected in the interior of the ignitioncoil to the one end of the primary winding, so that it is grounded. Theother end of the secondary winding may be connected to the high-voltageoutlet, which in turn may be either connected to an ignition cableleading to the spark plug, or at which the spark plug is set updirectly.

The secondary winding itself may be made of a thin wire coated with asuitable layer of enamel so as to avoid the contacting of the individualwires when wrapping a specific support part or coil shell. After thesecondary windings have been wound onto a shell, the ends of therespective wires are contacted. Thermal contacting methods such assoldering or welding, for example, may be used for this purpose.

Different work processes may be required, such as, for example, withregard to contacting the primary and secondary windings. This may entailhigher installation costs, multiple assembly steps and also a certainnumber of connecting parts required to make an appropriate electricalconnection.

Furthermore, in a tight installation space, it may be difficult to bringabout an appropriate contacting using conventional thermal methods.

SUMMARY OF THE INVENTION

The present invention may provide a connection set-up between anignition coil rod of an ignition coil and a secondary or primary windingwhich is inexpensive and readily implemented.

According to an exemplary embodiment of the present invention, theconventional thermal contacting method may be replaced by providingadditional contacting elements that break through the enamel-coated wireof the secondary winding during installation, thus bringing about anappropriate contacting.

In particular, it may be seen as desirable for the electrical connectionset-up for producing an ignition coil, that the contacting be integratedinto already existing components, and may be reliably produced usingsimple processes.

Compared to the conventional method, a “cold” contacting method proposedhere may involve no additional installation costs. In addition, theset-up of the present invention may reduce the number of assembly stepsand the number of connecting parts.

According to an exemplary embodiment of the present invention, theimplementation of the contacting does not require optimization of theinstallation space. Thus, it may not be necessary to reserve a freespace in the area of contacting, e.g. for electrode holders, solderingirons or the like.

Simply by sliding a contact sleeve onto the coil shell configured as asecondary winding, this contacting body may be slid directly onto thecoil shell without shifting the installed secondary winding. This may beachieved by the feature that the contact sleeve is slit lengthwise andmay thus be opened up as a spring.

This contact sleeve may feature contact clips on its outer surface,which, after the contact sleeve has been slid onto the coil shell,contact the wire of the secondary winding due to their spring-like formin that the contact clip of the contact sleeve breaks through theinsulation, for example, of an enamel coating of the wires of thesecondary winding.

The contact sleeve may be guided over the coil shell until it strikesagainst a stop formed on an ignition coil rod. To prevent damaging orshifting the secondary wire, the diameter of the contact sleeve may belarger or at least equal to the diameter of the secondary shell andtwice as large as the diameter of the wire. As soon as the contactsleeve is positioned in a very straightforward manner in the contactingarea of the ignition coil rod, it may be installed in the ignition coilhousing with the high-voltage outlet. By insertion into a cup-shapedformation, the contact clips are pressed onto the winding of thesecondary winding, thus breaking through the insulating layer of thewire and establishing a permanent electrical contact. The free end ofthe winding of the secondary wire may be wound around a pin-likeformation at the end of the ignition coil rod. This pin is then insertedinto the high-voltage outlet. This may prevent failures of the ignitioncoil due to superelevations of the field at the end of the wire.

A space-saving alternative may provide for rupture joints on thepin-like formation of the ignition coil rod so that, when the assemblyis installed into the ignition coil housing, the pin on the side of thehigh-voltage outlet breaks, and specifically inwardly so that contact isensured in spite of the break.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of an ignition coil having one side forthe high-voltage outlet and another side for the low-voltage outlet.

FIG. 2 shows a sectional view through the ignition coil according toFIG. 1.

FIG. 3 shows an enlarged representation of the perspective view of theside of the high-voltage outlet of the ignition coil rod.

FIG. 4 shows a section through the enlarged view of the side of thehigh-voltage outlet according to FIG. 3.

FIG. 5 shows a perspective view of the contact sleeve for installationon the side of the high-voltage outlet.

FIG. 6 shows a sectional view of the contact sleeve according to FIG. 5.

FIG. 7 shows an enlarged partial representation of the contact clips ofthe contact sleeve according to an example embodiment of the presentinvention according to FIG. 6.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view of an ignition coil 1. Ignition coil 1includes an ignition coil housing 2 and an ignition coil rod 3 locatedin ignition coil housing 2. In addition, ignition coil 1 features a sidefor a high-voltage outlet H and a side for the low-voltage outlet N. Theside of low-voltage outlet N is provided to establish contact with apower supply not detailed in the drawing, while the side of high-voltageoutlet H is provided for connecting to an ignition cable or a spark plugnot detailed in the drawing.

FIG. 2 shows a sectional view of ignition coil 1 represented in FIG. 1,the areas shown relating to essential features of the inventionrepresented in more detail in the subsequent figures.

On high-voltage side H, a contacting area 20 (FIG. 3) is provided onignition coil rod 3, which provides for the installation of a secondarywinding 22 on a coil shell 21. Following the completion of the windingof secondary wire 22, it is guided through a bore hole 23 intocontacting area 20, where it is further wound until it enters a groove24 and reaches a pin 25. At pin 25, the free end of secondary wire 22 istied up.

A contact sleeve 26 depicted in FIGS. 4 through 7 is now put overcontacting area 20. This contact sleeve 26 has at least one axial slit27, which, for example, does not extend over the entire length. Inaddition, provided on the peripheral surface of contact sleeve 26 is atleast one contact clip 28 for establishing a contact with secondarywinding 22 in contacting area 20 on the side of high-voltage outlet H.

By virtue of axial slit 27, contact sleeve 26 is now guided overcontacting area 20 of ignition coil rod 3 on the side of high-voltageoutlet H until it reaches a stop 29. The expansion of contact sleeve 26while sliding it on prevents secondary winding 22 on the side ofhigh-voltage outlet H from being damaged. Contact sleeve 26 isconfigured so that it reaches a press fit immediately after it has beenslid over the contacting area, preventing contact sleeve 26 from fallingoff again.

As shown in FIG. 4, this assembly made up of ignition coil rod 3 andcontact sleeve 26 is now installed into high-voltage outlet H ofignition coil housing 2. Ignition coil housing 2 features a cup-shapedformation 30 for receiving the free end of ignition coil rod 3. Inaddition, a recess 31 is provided for receiving pin 25 of ignition coilrod 3.

Due to cup-shaped formation 30 of ignition coil housing 2, contact clips28 of contact sleeve 26 are pressed in a defined manner in the directionof an arrow 32 (FIG. 4). The insulating layer of secondary wire 22 isthereby pierced and an electrical contact permanently established. Thefree end of secondary wire 22, which is wound around pin 25, is insertedinto recess 31. At the same time, stop 29, located on the side ofignition coil rod 3, rests on a shoulder 33 on the side of ignition coilhousing 2. By integrating the contacting option and existing components,contacting options may be created between components and the secondarywinding in an ignition coil via simple joining operations, while savingadditional installation costs, assembly steps and the like.

1. An electrical connection arrangement for an ignition coil,comprising: a coil shell having a secondary winding including at leastone contacting area; a contact sleeve at least partially slit lengthwiseand configured to be placed over the at least one contacting area, thecontact sleeve having an inner side configured to cooperate with thecoil shell, and the contact sleeve having at least one contact clip withcontacting elements on a side facing the coil shell; and a cup-shapedformation of the ignition coil configured to receive the contact sleeve;wherein the contacting elements are configured to break through aninsulting layer surrounding the secondary winding during theinstallation of the contact sleeve in the cup-shaped formation toachieve contact with the secondary winding.
 2. The electrical connectionarrangement of claim 1, wherein the ignition coil is a rod-type ignitioncoil including an ignition coil rod having a high-voltage outlet and alow-voltage outlet, and the contact sleeve is configured on ahigh-voltage outlet side of the ignition coil.
 3. The electricalconnection arrangement of claim 2, wherein the contact sleeve isinstalled in a press fit over the at least one contacting area.
 4. Theelectrical connection arrangement of claim 3, wherein the contact sleeveis configured to be opened up as a spring.
 5. The electrical connectionarrangement of claim 3, wherein, in an installed state in an ignitioncoil housing and by cooperation with the ignition coil housing, the atleast one contact clip is configured to lie against the at least onecontacting area and establish an electrical connection.
 6. Theelectrical connection arrangement of claim 3, wherein the high-voltageoutlet includes an end having a pin configured to engage in a recess ona side of an ignition coil housing of the ignition coil in an installedstate.
 7. The electrical connection arrangement of claim 6, wherein thepin is provided for winding up one end of the secondary winding.
 8. Theelectrical connection of claim 6, wherein the pin includes at least onerupture joint.